This application is directed generally to the problem of properly positioning a sample for testing within an analysis instrument of the type which presents a generally elongate cylindrical test chamber, and more particularly to a positioning apparatus for presenting a sample for analysis in such a device.
While the apparatus of the invention may find other applications, the invention will be particularly described herein with reference to the problem of positioning an object or sample to be presented to an electromagnetic analysis apparatus. One such apparatus is generally shown and described in U.S. Pat. No. 4,496,907 which is commonly owned herewith. In this prior U.S. patent, a test apparatus is shown which utilizes an electromagnetic field in order to determine conductivity-related properties of a sample of material which is introduced into the apparatus. This test apparatus may be utilized for testing relatively uniform bulk materials, such as agricultural grains, samples of prepared ground meats and the like in agricultural commodities-related applications.
Similar apparatus for measuring certain properties of human or animal subjects is shown and described in U.S. Pat. No. 4,727,330, which is also commonly owned herewith. This apparatus also utilizes an electromagnetic field to determine conductivity-related properties of the subject.
When using test apparatus similar to those shown in the above-referenced U.S. patents with small animals in laboratory settings, some difficulties arise. For example, it is generally desirable to present a sample or subject of generally uniform shape and orientation, and to hold the subject substantially centered with respect to the electromagnetic field in the measurement chamber of the measurement device or apparatus. This is desirable primarily to assure uniformity of shape and orientation from one sample or subject to the next, and hence to assure relatively uniform measurement results from one sample or subject to the next. Generally speaking, the laboratory animal presented to the test instrument is living, however, the animal may or may not be anesthetized. Such laboratory animals are generally irregular and non-uniform in shape, and may therefore be difficult to properly present for analysis.